Work from our past Udall Center application (2004-2009) provides compelling genetic, genomic and biochemical evidence that over-expression of wild-type a-synuclein is a major risk factor for Lewy body disease. Past genetic discovery has immediately improved diagnoses for rare families, and has lead to industry-sponsored translational programs in RNA interference targeting the a-synuclein gene. However, our (PD, PDD, DLB and MSA), and the role of a-synuclein is in its infancy. Project 1 has four aims to addr s these issues: Aim 1 Exonic sequencing of multi-incident family with clinical parkinsonism and autopsy confirmed Lewy body disease. As our preliminary data illustrates, the methods used provide a rapid and cost effective way to identify novel gene mutation(s) in disease. Aim 2 is for comprehensive SNCA genomic capture and re-sequencing of asynucleinopathies, to enable comparative genetic association studies of clinical and pathologic phenotypes across a range of Lewy body disorders. We need to identify the precise variants that influence disease risk, and their molecular mechanism. Work in Aim 3, using a subset of the best characterized samples, will provide complementary data from whole genome transcriptome analysis in a-synucleinopathies. Lastiy, Aim 4 will characterize the role of endogenous miRNA in the regulation of a-synuclein expression. The project could not be accomplished outside of a Center;it rests heavily on resources and expertise offered by Cores B, C and D, and will reciprocally inform research in Projects 2 &3. Our objective is to provide meaningful molecular diagnoses to reclassify this heterogeneous group of diseases. We aim to provide a mechanistic understanding of the pathogenesis of Lewy body disorders through gene discovery, and for a-synuclein and its homologues, exploiting advances in next-generation sequencing methods.